Postdetection switch-and-stay diversity in Rician fading

Recent work has examined the performance of dual branch postdetection switch-and-stay combining (SSC) for noncoherent binary orthogonal frequency-shift keying (BFSK) and noncoherent M-ary orthogonal frequency-shift keying (MFSK) operating in the presence of slow, flat fading modeled by Rayleigh, Nakagami-m, and Rician distributions. These studies are important, in particular, because they quantify the improvement of postdetection SSC over predetection SSC. However, previous work on the performance of postdetection SSC over Rician fading is incorrect. In this paper, we present correct analyses of the bit error rate (BER) performance of BFSK and MFSK with dual-branch postdetection SSC in Rician fading. Extensive Monte Carlo simulations are carried out to verify the validity of the analytical results. Our results show that the performance gain of postdetection SSC over predetection SSC is much less than previously reported.